One of the ways to make your home more energy-efficient is to install a programmable thermostat and timer for the water heater.  (© Steve Gorton/Getty Images )

One of the ways to make your home more energy-efficient is to install a programmable thermostat and timer for the water heater.

1. Replace your refrigerator
This is one of the biggest energy-guzzling appliances in the house, says Lisa Dornan, spokeswoman for Direct Energy, and there have been big changes in the efficiency of this appliance over the last five years. "If you look back at the top-rated refrigerator in 2001 that was Energy Star, and one you'd buy today with an Energy Star rating, there would be a 20% to 40% difference in energy efficiency," she says. Her firm, Direct Energy, performs home energy audits and is an energy retailer. Replacing older dishwashers and dryers can make a big difference too, she adds.

2. Install a programmable thermostat and a timer for the water heater
Just as you would flip off the lights before heading out to work, you should turn the heating or cooling off or down while you're away. Program the thermostat for a higher temperature when you're gone in warmer months, or lower in cooler months. These thermostats can be had for $150 at big-box hardware stores.

Likewise, don't heat your water when you're not there to use it. "You definitely want to make sure you are not heating the whole tank needlessly," Dornan says.

Tankless water heaters can be a great investment too, she adds, but they may take a few years to pay for themselves.

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3. Put a solar film or solar shades on the outside of windows to cut the heat
If you're moving into a house with single-paned windows, or living in a climate with extreme heat, you should consider putting something on the outside to reflect the light, Arizona home inspector Scott Hubbard says.

4. Don't let the heat escape
Also, caulk window and door frames to make sure they are airtight. And if possible, use honeycomb-type shades on the inside to trap the heat before it is absorbed into the room.

5. Use compact fluorescent bulbs
This is kind of a no-brainer, experts say, because it's so cheap to do and saves so much on your electricity bill. "Just for swapping out 10 light bulbs (in my home), I was able to get $400 a year in energy savings," Dornan says.

6. Change the filter on your air conditioner regularly
This monthly maintenance helps it run more efficiently, Dornan says, and minimizes wear and tear on your unit. Arranging furniture so it doesn't block air vents also is important to maximize the flow of cooling from your system.

7. Put in shady landscaping
Planting a tree or some vegetation outside a big window can shade your house from the strongest rays of the sun and stifle freezing winds. Planting low-water native plants can also cut your water bill, lowering the total cost you pay for you home each month. (See this slide show on 16 water-wise plants and read more about planning a drought-tolerant garden.)

8. Invest in an attic fan
These inexpensive fans can make a difference in the temperature of the whole house and keep your air conditioning from working so hard.